Follow TV Tropes


Literature / Division by Zero

Go To
Art by Noah.

"If everyone in a universe is slaughtered, who mourns their loss?"
— Kohana Outtaike, (ii: shored against the ruins / drowning in ten different directions.)

Division by Zero is a Science Fantasy web serial novel written by Solange Salgado. Influenced by shōjo and shōnen manga, it follows the life of Kohana Outtaike, a naïve 15-year-old girl who makes up for her idealism in endless sarcasm. Visited by an alien from another universe named Hiroyuki D'accardi, she is told she is a cosmic weapon called a Summoner and must assume her role as his planet's extraterrestrial war general. She is 1 of 8 Summoners, and is encouraged by Hiroyuki to find the others scattered throughout the cosmos. Kohana is a Magical Girl who refuses to be beaten no matter what; using her universe-destroying powers, she must fight those who are as strong as her in order to protect the multiverse from a great, unknown evil.

A Cosmic Horror Story, Kohana fights Eldritch Abominations called Shadows who travel the multiverse destroying planets for fun. They are led by a being called the umbrakinetic who strengthens their assault on the Earth as Kohana comes into her power. With time running out, Kohana must learn how to use her powers and protect her world. It's easier said than done, what with her finding herself Out of the Frying Pan often.


Division by Zero sees sporadic updates, though tries to do so once a month.

This story contains examples of:

  • The Ace: Though Kohana is labeled a prodigy by Celestial Beings, Hiroyuki himself admits Isleen is leagues above her in terms of magic and ability. During Isleen’s introduction in chapter 3, she saves Kohana’s life and plows through a horde of Shadows with little effort. Where Kohana struggles with invoking her magic, Isleen displays mastery over hers. Hiroyuki does not feel the need to explain things to Isleen. In fact, he mentions Isleen uses abilities that are too advanced for Kohana to grasp at her current level, and is so impressed by her that he is convinced Isleen has known she is a Summoner for a while.
  • Action Bomb: D'ivoire can cause explosions on contact.
  • All-Loving Heroine: In her narration, Kohana flat out says she would have died for all the people in the universes that were destroyed if it would have saved them.
  • Advertisement:
  • Ambiguously Evil: Hiroyuki and Jinnouchi’s conversation at the end of chapter 3 reveals that Hiroyuki has known who the umbrakinetic is all along and has both chosen not to say anything to Kohana about it and to do nothing about them. When questioned about this, Hiroyuki refused to answer her.
  • Anti-Hero: Hiroyuki is Good Is Not Soft personified. He presents himself as a soldier in name only, being mild, kind, and overall gentle in personality. One wouldn't know he was Spectra's World's Best Warrior unless he told them. He is by far the most peaceful character in a/0, and even goes as far as to avoid fighting Shadows altogether, at most dodging their attacks. Kohana wants to hate him and is frustrated that she can't, he has a humbleness that makes him unusually easy to get long with. All her suspicions of him being evil are routinely dashed by his kindness. Behind his good nature, however, is an assassin will not hesitate to kill children from the greater good. Unless you are Kohana, he will leave you for dead if The Needs of the Many becomes a problem. Cold-Blooded Torture is not above him. Neither is subjecting his victims Fate Worse than Death, the latter of which he states he prefers. Even his loyalty to Kohana is called into question when he watches her nearly die on several occasions.
  • An Axe to Grind: Tasi's Celestial Weapon is a Venetian carnival mask that can turn into a war axe.
  • And I Must Scream: Vasche, who becomes a part of Kaede's body, whose own body then turns against itself and kills him.
  • Animal Eyes: Kohana has cat pupils.
  • Apocalypse Maiden: Comes with the territory of Kohana being a universe-destroying weapon. She has decided to use her powers for good, however.
  • Archnemesis Dad: Gender Flipped: Kaede becomes this to Kohana when it is revealed she is the umbrakinetic. She played the role of an over-affectionate parent just to make Kohana’s breakdown all the more sweeter when she realizes how she really is. Because Kaede is the umbrakinetic, the two of them are destined to be enemies. Kaede expresses a long-standing dislike towards the Celestial Beings, and Kohana has decided she will stop Kaede from destroying the Earth (and any other planets she and her Shadows come across) as Spectra's general.
  • A Wolf in Sheep's Clothing: Isleen is a shapeshifting wolf who has decided to make herself look as dainty and fragile as possible.
  • Badass Army: The Special Operations Force is composed out of the top 20 or so soldiers in the Academy that were not able to become the Advisor. Because only one person can become the Advisor, these soldiers are just as strong as them, if not more so. When the SOF appear in the story, they arrive on earth to rescue Kohana and Hiroyuki after the latter's ship is destroyed by the umbrakinetic. They are competent enough to hold their own against Shadows, with one of them going as far as to Wow Cthulhu.
  • Barrier Warrior: Kohana is fond of creating space-time barriers.
  • Be Careful What You Wish For: Kohana has desperately wanted to meet aliens for years. She meets Hiroyuki. She has been crying every chapter since.
  • BFS: Kohana's sword, the Star Stealer, is a 7'4" ōdachi.
  • Big Bad: Kohana spends the first few chapters fighting Shadows and searching for the umbrakinetic, only for the umbrakinetic to be her mother Kaede, the second named villain in the story after Jinnouchi.
  • Bodyguarding a Badass: It has been said many times that Kohana is capable of destroying universes. Hiroyuki is almost certainly protecting everything else from Kohana rather than it being the other way around.
  • Boomerang Bigot: Blaire isn't fond of Spectrians for their tendency to fight everything that moves. In explaining this dislike to Kohana, she mentions she is smarter than the average Spectrian and would never stoop to such lows. She also refers to members of the SOF as rejects but is a member of the SOF herself.
  • Brutal Honesty: After Kohana tells the SOF she won't abandon the Earth, Blaire bluntly tells her she is too idealistic and reminds her she can't change anything, dead or not. This happens again during the two's meeting with the Commander in chapter 5 where Kohana is upset Blaire keeps saying the Earth is dying. Blaire snaps back and tells Kohana she won't sugarcoat anything she says to her and insist she be honest with herself instead of getting comfortable in her idealism.
    Blaire: What do you want me to say? That it’s alive and thriving? You said it yourself, the Earth has seen better days before we even got there. Listen, I’m no Hiroyuki. I’m not going to tiptoe around your feelings or let you continue to say nonsensical things. If I have to play Advisor for the day, you’re going to get it raw. You need to come to terms with the fact that the Earth is gone. The sooner you can put it behind you, the sooner you can focus on what lies ahead. It gets worse from here. You haven’t seen anything yet.
  • Bullet Time: As the Summoner of Time, Kohana's mind and body process information at such absurd speeds that time slows down, enabling her to perceive what would normally be too fast to see and respond accordingly. She is able to perceive events with unwavering focus and avoid linear attacks with incredible ease.
  • The Call Knows Where You Live: Had Kohana not Refused the Call, she might have been able to prevent her school from being destroyed by Shadows. Even worse is that it is implied her mother was killed in the attack. Kohana is briefly terrorized by the very real possibility of her mother’s passing, but is too blindsided by Jinnouchi being a Shadow to dwell on it for long.
  • Cast Full of Gay: Kohana has a crush on Isleen. Hiroyuki stutters over his words when he contacts D'ivoire, and mentions how attractive he is. Isleen, at the very least, acknowledges Kohana’s crush by flirting with her.
  • Celestial Body: The Celestial Beings of Spectra. Exactly what it says on the tin.
  • The Chosen One
  • Child Eater: The Shadows eat those who stayed after school in chapter 3, including the teachers.
  • Child Soldiers: Kohana is 15-years-old, 16-years-old as of the time skip in chapter 4, and has to lead Spectra in an eons-old war against the umbrakinetic as the planet's general. She knows nothing about warfare and has no training prior, essentially thrown to the wolves on the assumption that she should survive because Summoners 'have an inherent aptitude for battle.' Not only is she up against the umbrakinetic who can kill anything she wants whenever she feels like it, she has to fight wars the umbrakinetic starts on other planets to prevent them from being destroyed.
  • Commander Contrarian: Blaire.
  • Complete Immortality: The Commander of Spectra.
  • Cradling Your Kill: Hiroyuki apologies to Jinnouchi before she is 'sent away' by him.
  • Crouching Moron, Hidden Badass
  • Determinator: One of Kohana's defining traits. She will wholeheartedly die before she ever gives up.
    Kohana: I do not try, I do. Try insinuates a half-heartedness I am not capable of. I give everything my all and then some, even if my end goal is small. I don’t know how to make ‘attempts.’ I move heaven and earth for what I aim to accomplish.
  • Did You Just Punch Out Cthulhu?: D'ivoire does this after the umbrakinetic kills two members of the SOF. He swoops in and blows up four of her arms with his explosive touch after the umbrakinetic was previously shown to be impervious to damage. She is suprised when this happens. She waits her arms to regenerate, and is annoyed when they don't. He then goes on to detonate himself to rub more salt in her wounds.
  • Enemies with Death: Turns out the umbrakinetic is an ancient god from another planet that is the multiversal manifestation of death capable of killing anything and everything in the multiverse outside of the Summoners who were created specifically to deal with it.
  • Expecting Someone Taller: The Commander of Spectra lords over billions of soldiers and rules the planet with an iron fist, leading Celestial Beings on star conquests that leave universes barren, not to mention he created the Summoner Project. When Kohana finally meets him, she does not hesitate to comment on his height despite his achievements.
    Kohana: So you’re the guy who’s in charge. Thought you’d be taller.
  • Face Death with Dignity: Jinnouchi has a calm conversation with Hiroyuki knowing he will ‘send her away.’
  • Force and Finesse: Isleen is a Berserker and Kohana is a Dance Battler.
  • Forever War: Spectra and Alraera have been at war for eons over the former trying to eat one of the latter’s stars. Neither side has tried to reason with the other since, and Spectra has not made another move to eat the star. The war has no foreseeable end, with Kohana being told she must find and kill the umbrakinetic. She is not told if doing so will end the war or not.
  • Freudian Trio:
  • Hair-Trigger Temper: Kohana.
    Hiroyuki: She is certainly aggressive, so easily offended and ready to bicker even when her life is being threatened. I am counting on that belligerency, how she is prepared to stand and fight the smallest thing that makes her angry.
  • Handicapped Badass: T'whami is a scientist, a member of Aysel's Royal Guard, is missing an arm, an eye, and her body is marred with scars. Her prosthetic arm is fitted with claws, and is sturdy enough to take the force of hypercharged bullets. Despite lacking an eye, T'whami's perception is impeccable. She is able to keep up with gunfire and position her arm in such a way to deflect each individual bullet.
  • Heroic BSoD: Kohana suffers one when she returns to her school and sees the Shadows have killed everyone there. Her shock is so extreme that Hiroyuki compares her reaction to that of a war-weary soldier. Her Heroic BSoD is made worse when the Shadows deliberately start eating the corpses of their victims. She promptly blacks out, only for Hiroyuki to force her to regain consciousness by using his magic.
  • Heroic Sacrifice: Vasche.
  • He Who Fights Monsters: Deconstructed. Kohana knows turning into a monster from fighting Shadows is a strong possibility. It is one of her worst fears, in fact, especially after what the Shadows do to her school. The Shadows' wrongdoings keep her honest and moral, as they are a constant reminder of what she could become. Because Kohana refuses to become a monster, she tends to humanize the Shadows in her narration, sometimes to a fault. While her hatred for them is evident, at times she finds herself wondering if they think of the umbrakinetic like a mother, or if they have feelings. This moral dilemma comes to a head in chapter 4 when Blaire tells Kohana she should kill umbrakinetic and get it over with. Kohana responds by saying she won't kill them or anyone for that matter, and raises the question of how killing the umbrakinetic would make her any different from them.
  • Horrifying the Horror: When it comes to Isleen, Shadows want no part of her. During her introduction, droves of them try to run away from her after causing widespread destruction and killing countless civilians. She does not let them.
  • Ice Queen: Isleen. Kohana finds it difficult to even start a conversation with her. It does not help that Kohana instantly develops a crush on her and feels rejected when she turns down her attempts at smalltalk.
  • Inhumanly Beautiful Race: The Celestial Beings. Kohana is heavily implied to be Celestial as well, sharing their shimmering hair and glowing eyes.
  • "I Know You're in There Somewhere" Fight: Defied. In chapter 3 it is revealed Jinnouchi is a Shadow. Not only does Kohana refuse to fight her, Isleen deals a killing blow to Jinnouchi by running the Star Stealer through Kohana and into her late instructor.
  • Lady Swearsalot: T'whami has no filter whatsoever.
  • The Lancer: Where Kohana proposes naïve solutions to problems, Isleen challenges them with cold logic.
  • Lightning Bruiser: Kohana can eat world-ending blasts, move faster than a blink, and is so strong she can create an earthquake by clapping her hands.
  • Love at First Sight: Hiroyuki notices right away that Kohana has a crush on Isleen, vowing to keep her crush a secret. Kohana knows and has admitted she is a hopeless romantic and falls in love easily, but this is the first time we have seen Kohana develop feelings for anyone.
  • Magical Girl Warrior
  • The Mentor: Hiroyuki to Kohana.
  • Multi-Armed and Dangerous: Kaede.
  • No Sympathy: Several of the characters have none in regards to Kohana.
    • The Commander doesn't care about Kohana still reeling over the fact that the Earth may be lost to Shadows or that she may never be able to return to it again. In fact he's eager to get Kohana on the frontlines to fight the umbrakinetic as soon as possible, thrusting her into another war as soon as she wakes up from her ordeal on Earth. When Kohana tells him her mother is the umbrakinetic, he bluntly tells her there is no way to seperate the two and tells Kohana she needs to kill her mother to defeat the umbrakinetic. When Kohana tells him she doesn't want to be a Summoner anymore because of what she has to do and what she's seen, he tells her she's useless anyway and claims he would not miss her.
    • Though unsympathetic to the entire cast, Blaire is especially unsympathetic to Kohana. When Kohana expresses exhaustion over fighting Shadows and being upset at the destruction they cause and the people they kill, Blaire laughs at and mocks her. She writes off Jinnouchi's death by telling Kohana 'big whoop' and doesn't think it's a big deal that her teacher died in front of her. Blaire figures out Kohana's mother must be the umbrakinetic after spending a few hours on Earth and is angry Kohana spent months tip-toeing over the possibility when she could have slain her. Blaire holds Kohana to a high standard because she is the Summoner of Time and doesn't believe Kohana should be wasting time crying when she has the power to defeat her enemies.
    • Hiroyuki ensures Kohana is painfully aware of her position as the Summoner of Time and doesn't give her the luxary of mourning those who die. He flat out admits he manipulates and uses Kohana's hero complex against her to keep her fighting regardless of what she endures. A notable instance of this is when Kohana passes out in her school after finding the corpses of her classmates and teachers. Hiroyuki immediately wakes her up with a stern reminder of what she is and who she needs to be to prevent a scene like that from happening again.
  • Oblivious to Love: Averted. Isleen understands Kohana has a crush on her and acknowledges it by taking joy in watching her squirm and stutter. She is not interested in returning Kohana's feelings, however.
  • Odango Hair: Kohana's hairstyle.
  • Offing the Offspring: Kaede tries to kill Kohana, complete with I Have No Daughter.
  • One Bad Mother: Kaede.
  • Parental Substitute: Right from the start Hiroyuki and Kohana have a father-daughter bond. This is especially important because she is on bad terms with her father.
  • Professional Killer: Hiroyuki describes himself as an assassin despite being kind, friendly, and everything contrary to what the general idea of an assassin is like. He insinuates a part of his job as an Advisor is to ‘remove’ those who prove to be too much for Kohana to defeat on her own.
  • The Quiet One: Isleen rarely speaks more than three words, and when she does she is either insulting Kohana or letting those in her company know how similar she is to Shadows in terms of bloodlust.
  • Skewed Priorities: Mildly put. Kohana is less worried about being killed by a Shadow and more worried about the fact that Hiroyuki won't help her defeat it.
  • Stand Your Ground: Hiroyuki tells Kohana this often. He does not hesitate to tell Kohana she is the only one who can save the Earth.
  • Rage Against the Mentor: In the second chapter, Hiroyuki reveals to Kohana that he and his people are responsible for the destruction of countless universes, and that she is a cosmic weapon meant to destroy them as well. She is horrified by this and lays into him.
    Kohana: Everything is your fault! All of it! The Shadow, the tree, whatever terrible thing that will inevitably happen to me because of your coming! You have ruined my life that fast!
  • Razor Floss: Kaede's spider web. She even has a Badass Boast about it.
    Kaede: My web is sharper than any blade. It slices through opponents of any form—immortal, invulnerable, incorporeal. It reaches every plane of existence. Metaphysical concepts such as time and space also prove no match for my web. Shield yourself and your comrades with your magic if you must, Summoner; my web destroys and negates conceptual defenses.
  • Refusal of the Call: Kohana initially refuses to accept her duty as the Summoner of Time by insisting she’s a ‘normal girl’ with a ‘normal life’ living on a ‘normal planet.’ This is notable, considering up until that moment Kohana wanted to be everything but. After Hiroyuki convinces Kohana she will be a hero if she embraces her role, she reluctantly dons the title.
  • Refuse to Rescue the Disliked: Subverted. Kohana does not like Blaire and says she would leave her for dead if it came down to it. When Kaede attacks, Kohana throws herself in front of Blaire and asks if she is hurt.
  • Rich Bitch: Blaire's introduction consists of insulting the entire cast. She looks down on everyone, especially Kohana, and generally views those around her as incompetent. She does not hesitate to tell Kohana how rich she is, and even 'brags' about how she bought her position in the SOF. She goes on to mention she would never stoop so low as to fight like the rest of her kind, and is proud to announce she gets people to fight for her. She is upset when Hiroyuki, D'ivoire, Tasi and Vasche jump to protect Kohana from Kaede's attack and do not immediately try to save her, even though she managed to jump out of harm's way anyway.
  • Shoot the Dog: Hiroyuki not only shoots the dog, he erases it out of existence, much to Kohana's horror. He removes the memory of all those who died in the attack on Kohana's school, and states his reason for doing so is because the planet would self-destruct if those people were remembered. Immediately following the attack, Hiroyuki even said he would kill any survivors he came across. His new position as Jinnouchi's replacement put him in the perfect position to do so, and since we know he has no qualms with killing children it is implied he did exactly that in the few-months time skip between chapters 3 and 4. Hundreds of teenagers, along with their teachers, are forgotten about as a result of Hiroyuki's actions. The parents of the children who passed away don't even remember having them.
  • Unreliable Narrator: Both Kohana and Hiroyuki fall under this. Kohana’s case is more severe due to metal illness, with Hiroyuki flat out stating she is histrionic. When her feelings are hurt, which they often are, she will throw whoever hurt them under the bus to either make herself look like a victim or to protect her ego. This is blatant when it comes to Hiroyuki, in which she tries to convince readers there is nothing kind about him when he upsets her. This can be especially confusing considering Kohana praises his kindness when she is not taking his actions as imaginary slights. Hiroyuki lends readers more credibility in his narration, but there are still things that conflict with what he says that take place in the story. Hiroyuki says he is unable to empathize with Kohana, for example, but becomes frustrated on her behalf in his narration when it is revealed her teacher gained Kohana’s trust and love only to use that against her.
  • Unskilled, but Strong: Kohana takes a planet-shattering attack point-blank and survives it without a scratch. She then proceeds to take this attack multiple times with increased intensity and, again, remains unscathed. The Shadow decides to eat her after it realizes it can't hurt her, which backfires horribly and causes it to explode. After pulling itself back together, the Shadow turns itself into an infinite amount of bullets and shoots itself at her; she dodges every single one, allows the Shadow to get close to her, and freezes it in place with her time magic.
  • Walking Spoiler: It’s impossible to talk about Kaede without giving her personality change and position as the umbrakinetic away.
  • World's Strongest Man: As the chosen Advisor, Hiroyuki is the strongest soldier on Spectra.
  • Would Hurt a Child: Jinnouchi, who outright admits she is the one who orchestrated the attack on Kohana’s school. Never mind the fact that she tries to break Kohana’s neck while confessing to killing children.

Example of: